One of the most unpleasant aspects of owning small indoor pets, such as cats, is the cleaning of pet excrement from liter boxes. These litter boxes are containers that are filled with granular pellets that cover and absorb animal waste left when pets relieve themselves within the box. Litter boxes require regular and thorough cleaning in order to prevent an unhealthy environment for both the pet and the homeowner. The frequent cleaning of these boxes also limits the possibility of pet excrement being picked up on the pet's feet and tracked through the home. A cat is the most common pet to use a litter box. With a cat, there is also the problem of the cat scattering the soiled litter from the box in an attempt to create clean areas in the box to relieve themselves. The failure of the owner to regularly clean the boxes results in very unpleasant odors and eventually the pet will cease to use the box altogether.
The pet owner usually maintains a clean litter box by either of two methods. One method is by frequently changing out all the litter in the box each time the box is cleaned. The other method is by removing only the solid excrement and allowing the litter in the box to absorb the pet urine until the litter becomes saturated. Then all the litter is finally disposed of. By removing the solid excrement and not disposing of the entire box of litter, the pet owner can still adequately maintain a clean and acceptable litter box and at the same time, enjoy a considerable cost savings over the first method.
There are several patents that have disclosed various approaches for separating the sold excrement left in the litter box from the litter itself. These devices usually take advantage of the fact that the litter particles are considerably smaller then the solid pet waste. Therefore, separation can be achieved by having the litter fall through some type of perforations that are sized to be large enough to let the litter pass through easily and yet small enough to retain the solid excrement. Examples include: U.S. Pat. No. 4,325,325 to Larter, which is comprised of two matching interconnecting litter boxes and a removable, perforated, separator plate that is placed between the boxes. Upon inverting the boxes, the separator removes the solid excrement from the first container by allowing only the "cleansed" litter to flow through the perforated plate and into the second container. The solid excrement is then disposed of from the perforated plate. Another example is U.S. Pat. No. 3,908,597 to Taylor, having double boxes with perforated bottoms and a slide-out solid divider. Removing the slide-out divider allows the "cleansed" litter to flow from one container to the other, at which point the top container is removed and the solid excrement disposed of. The top container is then replaced with a cap and the whole stack inverted to repeat the process. Other patents such as U.S. Pat. Nos. 4,602,593 to Gross, and 4,616,598 to Burniski, reveal improvements in cleaning litter boxes that incorporate novel means for opening and closing perforations in a previously solid floor. This allows the litter to sift through while trapping the solid pet excrement. Both of these patents incorporate movable parts activated by handles, cranks, or levers.
There still remains a need for a litter box that is truly simple and easily operated with minimal effort by even the sick, handicapped, or elderly. This box should not require the use of moving parts that can break, wear out, demand maintenance or incorporate additional components that must be stored separately and cleaned after each use. This desired litter box should also allow the owner to dispose of the removed solid pet excrement in a manner that is aesthetically appealing by not requiring the operator to have direct visual or olfactory contact with the pet excrement. Above all else, the litter box must be convenient and safe for the pet to use.